1. Field of the Invention
The present invention relates to a mechanism for deflecting a headlamp optical axis, which does not use speed reduction gears, and further to a mechanism for swinging an object, which does not use speed reduction gears.
2. Description of the Related Art
Some headlamps mounted on the recent automotive vehicles come in an AFS (Adaptive Front-lighting System). The AFS allows light beam direction to be adjusted in response to driving conditions by swinging the entire headlamp assembly. A mechanism for deflecting a headlamp optical axis is disclosed, for example, in Japanese Patent Applications KOKAI Publications Nos. 2001-277938 (Paragraphs 0032 to 0034, FIG. 7 therein), 2002-326536 (FIG. 4 therein), and 2002-234382 (Paragraph 0009, FIG. 4 therein), which comes in an AFS, and which deflects a headlamp optical axis horizontally in accordance with degree of steering angle.
In a mechanism to deflect a headlamp optical axis disclosed in the aforementioned Japanese Patent Application KOKAI Publication No. 2001-277938, an actuator is provided under a headlamp assembly including a lamp and a reflector. As described in the aforementioned Japanese Patent Applications KOKAI Publications Nos. 2002-326536 and 2002-234382, each actuator includes a stepping motor and a plurality of gears adapted to reduce rotation speed of the stepping motor at a large ratio.
A conventional mechanism for deflecting a headlamp optical axis incorporated in an AFS employs a plurality of speed reduction gears as well as a stepping motor, thus requiring management of the gears, and hindering cost reduction. Also, increase in the number of gears employed involves a risk of increasing deflection error. The same problems are seen in a mechanism for swinging an object, which employs a plurality of speed reduction gears in addition to a motor.